Thigh Blast: Toned Legs With Smith Machine Squats


Shaping your thighs into pillars of long-limbed magnificence takes years of gut-busting effort – e.g., heavy barbell squats with enough resolve so you feel like your blood vessels will implode and scatter your lifeblood across the gym floor and walls. Such is the effort needed if you want to develop toned and shapely thighs that will turn heads at the gym or in the supermarket.

However, size is not the only objective of serious weight trainers. Sometimes you see a woman in the gym who has ultra-toned thighs, but she has not bothered to think much about symmetry – and she has failed to mold her thighs into sharp, carved pairs of marble. The result is that a smaller woman with harder and better-shaped legs looks better. This is because truly amazing thighs have some combination of size and thickness and also possess sharp and defined granite-like symmetrical muscle thigh bellies.

If you have been seriously lifting weights for a few years and your thighs are toned and developed, it may be time to reassess your training achievements and goals and think a bit more about thigh shape. That does not mean that you have a free ticket to slack off; what it does mean is that you should not depend solely on barbell squats for all your thigh development.

The Smith machine squat is one good way to supplement barbell squats. The Smith machine can help you maintain the overall fitness and development of your thighs, while simultaneously burning deep grooves between your muscle bellies in the front of your thigh. It allows a smooth, vertical lift (which is a bit different than a regular barbell squat) under constant tension and because it has built-in safety pegs, the Smith machine is also great for those who might want to lift heavier loads but prefer to work out alone.

Muscles Activated

The Smith machine targets the quadriceps muscles of the thigh quite strongly and differs a bit from regular barbell squats, which also strongly activate the erector spinae muscles of the back and the gluteal muscle group. The quadriceps femoris (“quads”) is a family of four muscles of the anterior (front) thigh. These include the rectus femoris muscle and the three vastus muscles. The fibers of the rectus femoris muscle (rectus=straight) run straight down from the hip, along the front of the thigh and join the quadriceps tendon above the kneecap (patella). The rectus femoris extends the leg at the knee joint. The rectus femoris begins at the hip bones, so when the hip is flexed (during the low part of a squat), it is slackened and therefore functionally weakened. The vastus medialis muscles cover the medial (inner) part of the thigh. The vastus intermedius muscle is positioned between the vastus lateralis and the vastus medialis muscle, but it is deep to the rectus femoris muscle. The vastus lateralis muscle is positioned on the lateral (outer) part of the thigh. The three vastus muscles begin on the femur bone of the thigh and all attach to the upper border of the patella by the quadriceps tendon. The patella is attached to the tibia bone of the lower leg by the patellar ligament. As the muscles of the quadriceps shorten, they pull on the tibia by way of the quadriceps tendon and patellar ligament, so the leg extends (i.e., knee straightens) at the knee joint. The three vastus muscles are not affected by hip angle, so they are active throughout the squat on the Smith machine.

Smith Machine Squats

It is wise to spend five minutes warming up your knees and thighs before any type of squat. This increases the blood flow to the knee structure and decreases the viscosity of the synovial fluid, which lubricates the knee joint during movement.

1. Place the bar on the Smith machine about 4-6 inches lower than your shoulders. Make sure the safety pegs are adjusted at the right height, so they will stop the bar if you get deep into the lift and can’t come up. Add the plates to the bar but start a bit lower than you would for a barbell squat, at least to begin with.

2. Face the bar and bend your knees slightly. Once you are under the weight, the bar should rest over the trapezius muscles in the same manner that you would have it sit in a regular barbell squat. You may want to wrap a towel or a foam pad around the bar to cushion it against the shoulders.

3. Twist the bar to unrack it and then straighten your knees. Take a small step backward from the rack. This will allow you to move vertically and help to concentrate the effort on the quadriceps. Place your feet about 10-12 inches apart. Although your foot position can be wider, most research suggests that wider foot placements will not improve the activation of the vastus muscles. You should also find a comfortable foot position with your toes pointed slightly outward (but not too much) because this will help you keep your balance. Try to keep your knees and toes in line.

4. Take a deep breath and slowly squat downward, taking about three to four seconds to reach the bottom position. Continue squatting until your knee angle is about 90 degrees of flexion. Keep your head up and look forward as you squat.

5. After reaching the bottom, stand up by straightening your knees. Do not “explode” out of a position with an extremely bent knee; this could cause serious injury. Starting slowly upward will help protect your knees in this vulnerable position. After you are partway up on the first rep and in subsequent reps, you may accelerate the weight upward; this will be especially effective in recruiting the largest and fastest fibers of your thigh. Of course, the other fibers will eventually be recruited, as you move closer and closer to the point of muscle failure, so it is important to push yourself hard as you complete the next repetitions.

6. You should avoid locking out your knees at the top position, because the stress will be removed from your quadriceps and the bones of the hips and thigh will transmit the force downward without the need for muscle activation. In fact, this becomes a superior exercise if you can maintain tension in the thighs throughout the entire lift. In addition, knee lockouts are bad for another reason – the knee joint can potentially sustain some training-ending damage in the fully locked-out position. This is because the weak anterior cruciate ligament of the internal knee can be easily torn, especially if the weight is heavy and “jerked” or exploded into the extended position.

7. The next repetition is the same as the first; the body is slowly lowered into the squat position but is raised with a healthy thrust upward.

8. Don’t forget that you must “rack” the bar at the end of your set. This means that you must not forget to give the bar a bit of a “twist” to engage the hooks to hold the bar. Of course, you can rack the bar wherever you fail.

Smith machine squats reduce the work of the gluteal and the spinal muscles and maximize the efforts of the quadriceps muscles (as compared to barbell back squats). However, because you don’t have to worry about balance, you should be able to lift pretty decent weights. This does not mean that you need to have “superwoman” efforts, as the knees are also under quite a bit of tension in the vertical squat on a Smith machine. For my money, medium-heavy weights with fluid motions and continuous tension work the best in this exercise. Further, you should not take too great of a step back from the rack, especially if you lock out your knees, because this will only accentuate the tension on knee ligaments.

If your feet are placed too closely together when squatting (i.e., 6 inches apart), this will produce a more acute angle at the knee during the lowest part of the squat, and this increases the risk of acute knee injury. This is particularly problematic if you drop too rapidly to the bottom part of the squat. The idea is to maximally work your muscles, but to have mercy on your knee joints.

All the squats in the world of any type will not necessarily “out-muscle” a hardworking and genetically gifted amazon. But Smith machine squats can help you move much closer to your fitness goals, by cutting grooves and deep valleys across your thighs, thereby transforming your thighs into toned and symmetrical towers of perfection!



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